Tag: evs

Questions Related to evs

Modern Kaleidoscopes are made of what?

evs magic with mirrors kaleidoscope uses of plane mirror reflected light can be reflected again

  1. Brass Tubes

  2. Stained Glass

  3. Wood

  4. All of the above

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Correct Option: D
Explanation:

Brass tube,stained glass and wood all are used to make kaleidoscopes. We can also make it at home with plastic, paper towel and some pieces of glass , beads and colorful items.

Some special kaleidoscopes which doesn't include objects at all are known as:

evs magic with mirrors kaleidoscope uses of plane mirror reflected light can be reflected again

  1. Teleidoscopes

  2. Telescopes

  3. Spy glass

  4. None of above

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Correct Option: A
Explanation:

Teleidoscope is a type of kaleidoscope with a lens which create patterns without any other objects in the tube.

An object is kept between two plane mirrors inclined at an angle $120$ from each other; calculate the number of images which are formed if the object is not on the bisector/on the bisector $3$

evs magic with mirrors kaleidoscope uses of plane mirror reflected light can be reflected again

  1. $\displaystyle \frac {3}{3}$

  2. $\displaystyle \frac {3}{2}$

  3. $\displaystyle \frac {2}{2}$

  4. $\displaystyle \frac {2}{3}$

Show answer
Correct Option: B
Explanation:

Given: An object is kept between two plane mirrors inclined at an angle 120 from each other

To find the ratio of number of images which are formed if the object is not on the bisector and on the bisector
Solution:
If there are two plane mirrors inclined to each other at an angle $\theta$, the number of images of a point object formed are determined as follows:

If $\left(\dfrac {360^\circ}\theta\right)$ is odd integer (say $m$) number of images formed
$n = m$, if the object is not on the bisector of mirrors
$n = (m – 1)$, if the object is on the bisector of mirrors.

So, when $\theta=120^\circ$, we get
$m=\dfrac {360}{120}=3$
So,
$\dfrac {\text{ number of images which are formed if the object is not on the bisector}}{\text{ number of images which are formed if the object is on the bisector}}=\dfrac {3}{3-1}=\dfrac 32$

Which of the following is the most important factor in balancing the amount of freshwater on earth?

evs rain: where does it come from sources of water and water cycle availability and forms of water the water cycle

  1. Water cycle

  2. Greenhouse effect

  3. Waste water treatment plant 

  4. Transpiration

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Correct Option: A
Explanation:

Water cycle is a continuous cycle in which water changes from water vapour in the atmosphere, through liquid water through condensation and precipitation and then back to water vapour through evaporation, transpiration and respiration. 

Among the given options, $A$ is the correct one. 

When water circulates through the water cycle it can be found in all the _________ form, at any given time somewhere on the earth.

evs rain: where does it come from sources of water and water cycle availability and forms of water the water cycle

  1. four

  2. two

  3. three

  4. six

Show answer
Correct Option: C
Explanation:

When water circulates through the water cycle it can be found in all the three forms, i.e., solid, liquid and gas at any given time somewhere on the earth. This continuous cycling of water in its three forms in nature keeps the total amount of water on earth constant even when the whole world is using it.

The circulation of water from surface of the earth to atmosphere and back to the surface is known as:

evs rain: where does it come from sources of water and water cycle availability and forms of water the water cycle

  1. water circle.

  2. water cycle.

  3. water round.

  4. None of the above.

Show answer
Correct Option: B
Explanation:

The circulation of water from surface of the earth to atmosphere and back to the surface is known as water cycle.

During water cycle, the water is circulated back from the earth in the form of:

evs rain: where does it come from sources of water and water cycle availability and forms of water the water cycle

  1. humidity.

  2. rain.

  3. vapour.

  4. None of the above.

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Correct Option: B
Explanation:

During water cycle, the water is circulated back from the earth in the form of rain or snow.

Hence, option B is correct.

The sideways reversal of the image by plane mirror is called :

evs magic with mirrors lateral inversion right or left reflection at plane surface

  1. lateral inversion

  2. parallax

  3. optical illusion

  4. magic

Show answer
Correct Option: A
Explanation:

The sideways reversal of the image by plane mirror is called lateral inversion

Lateral inversion is a feature of plane mirrors, in which:

evs magic with mirrors lateral inversion right or left reflection at plane surface

  1. The top part of the object appears to be the bottom part of the image.

  2. The left side of the object appears to be the right side of the image.

  3. Image appears to be inverted upside down and also sideways.

  4. All of the above.

Show answer
Correct Option: B
Explanation:
$ \bf{Lateral\ Inversion} $ is the phenomenon in which when looked through a mirror, the left-hand side of an object appears as right-hand side of the image and vice versa.

Hence, the correct answer is OPTION B.

An unlabeled analog clock is kept in front of mirror. Actual time on clock is 3. What is time in the mirror image?

evs magic with mirrors lateral inversion right or left reflection at plane surface

  1. 3

  2. 9

  3. 6.15

  4. 9.30

Show answer
Correct Option: B
Explanation:

Due to lateral inversion, hour hand of image points to 9. Minute Hand keeps pointing to 12. Hence, time in mirror image is 3.